The automobile dictionary meaning of the engine U1078 Code is found online and it is not necessary to use for any necessary purposes. The general meaning of the code is U means Network Code Problem is climate control system, lighting, airbags, etc. 1 means MFG – Manufacturer Specific. 0 means Fuel And Air Metering. 7 means Vehicle Speed Output Circuit and 8 for PCM Stack Overrun. The engine process, in conjunction with the engine control module or powertrain control module (PCM), activates the U1078 code solenoid valve to control oil compression to the engine instrument that is installed in the valve system to shift valve timing between Low and High.